In fabricating semiconductor devices, substrates are formed with designed patterns through a variety of processes such as photolithography, etching, ashing, ion injection, thin film deposition, and washing. An etching process is generally used for remove specific areas from films formed on substrates. The etching is usually classified into dry etching and wet etching. Dry etching is performed to employ a plasma etching apparatus. Plasma is typically generated by forming an electromagnetic field in a chamber. Such a electromagnetic field operates to excite a processing gas, which is supplied into the chamber, to a plasma state.
Plasma is referred to an ionic gaseous state formed of ions, electrons, or radicals. Plasma is generated under very high temperature, strong electric fields, or RF electromagnetic fields. Semiconductor device fabrication is performed along with etching processes using plasma. An etching process is performed by colliding ionic particles, which are contained in plasma, against a substrate.
An electrostatic chuck generally includes a supporting plate and a metallic body. The supporting plate is bonded to the metallic body through an organic bonder such as silicon or acryl. However, silicon is high in thermal tolerance but low in thermal resistance. Therefore, silicon is stable even to heat generating during substrate treatment, but insufficient to interrupt thermal transfer between the metallic body and the supporting plate. Acryl is high in thermal resistance but low in thermal tolerance. Acryl is effective in preventing heat loss between the supporting plate and the metallic body, but damageable due to heat generated during substrate treatment.
As introduced above, organic bonders used in substrate treatment nowadays are disadvantageous to endurance and weak to elevation of processing temperature, due to thermal fluctuation of electrostatic chucks, and could be melted down during high temperature processes.